#BBCtrending: Mapping ISIS followers around the world
20 June 2014 Last updated at 18:50 BST
The Sunni militants of ISIS aren't just taking over territory in Iraq - they're also trying to advance into people's social media timelines.
The Islamic State of Iraq and the Levant (ISIS) are spreading violent videos and propaganda messages using hashtags and even their own smartphone app - which was later removed after a an investigative report about it.
The BBC Trending team have mapped ISIS social media posts across the world. They tell a revealing story about the group's strategy and support.
Video journalist: Benjamin Zand
Presenter: Mukul Devichand
You can follow BBC Trending on Twitter @BBCtrending
All our stories are at bbc.com/trending